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Biosens Bioelectron. 2014 Jun 15;56:104-11. doi: 10.1016/j.bios.2013.12.051. Epub 2013 Dec 31.

Electrochemical aptasensor of cellular prion protein based on modified polypyrrole with redox dendrimers.

Author information

1
CNRS UMR-8182, Institut de Chimie Moléculaire et de Matériaux d'Orsay, Equipe de Chimie Bioorganique et Bioinorganique, Univ Paris-Sud, Bâtiment 420, 91405 Orsay, France.
2
Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynska dolina F1, 84248 Bratislava, Slovakia.
3
CNRS UMR-8182, Institut de Chimie Moléculaire et de Matériaux d'Orsay, Equipe de Chimie Bioorganique et Bioinorganique, Univ Paris-Sud, Bâtiment 420, 91405 Orsay, France. Electronic address: hafsa.korri-youssoufi@u-psud.fr.

Abstract

This work consists of the development of an electrochemical aptasensor based on polyprrole modified with redox dendrimers, able to detect human cellular prions PrP(C) with high sensitivity. The gold surface was modified by conductive polypyrrole film coupled to polyamidoamine dendrimers of fourth generation (PAMAM G4) and ferrocenyl group as redox marker. The aptamers were immobilized on the surface via biotin/streptavidin chemistry. Electrochemical signal was detected by ferrocenyl group incorporated between dendrimers and aptamers layers. We demonstrated that the interaction between aptamer and prion protein led to variation in electrochemical signal of the ferrocenyl group. The kinetics parameters (diffusion coefficient D and heterogeneous constant transfer ket) calculated from electrochemical signals demonstrate that the variation in redox signal results from the lower diffusion process of ions during redox reaction after prion interaction due to bulk effect of larger protein. The association of redox dendrimers with conducting polypyrrole leads to high sensitivity of PrP(C) determination with detection limit of 0.8 pM, which is three orders of magnitude lower, compared to flat ferrocene-functionalized polypyrrole. Detection of PrP(C) in spiked blood plasma has been achieved and demonstrated a recovery up to 90%.

KEYWORDS:

Aptamer; Biosensor; Cellular prions; Dendrimers; Electrochemical; Polypyrrole

PMID:
24480126
DOI:
10.1016/j.bios.2013.12.051
[Indexed for MEDLINE]

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